Novel Compounds and Methods for Forming Taxanes and Using the Same

ABSTRACT

The present invention is broadly directed to novel compounds useful for the synthesis of biologically active compounds. More particularly, the present embodiments disclosed herein relate to novel side chains, that when coupled to a taxane, are useful for the synthesis of pharmaceutically useful taxanes. Methods of forming the novel side chains and coupling them to hindered alcohols, namely taxanes resulting in useful esters are also disclosed. Various taxanes compounds are known to exhibit anti-tumor activity.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation-in-Part of U.S. patent applicationSer. No. 10/951,555, filed Sep. 27, 2004 and PCT Application No.PCT/US04/31816 filed Sep. 27, 2004, both of which are currently pending.

FIELD OF THE INVENTION

The present invention is broadly directed to novel compounds useful forthe synthesis of biologically active compounds. More particularly, thepresent embodiments disclosed herein relate to novel side chains, thatwhen coupled to a taxane, are useful for the synthesis ofpharmaceutically useful taxanes. Methods of forming the novel sidechains and coupling them to hindered alcohols, namely taxanes resultingin useful esters are also disclosed.

BACKGROUND OF THE INVENTION

Various taxane compounds are known to exhibit anti-tumor activity. As aresult of this activity, taxanes have received increasing attention inthe scientific and medical community, and are considered to be anexceptionally promising family of cancer chemotherapeutic agents. Forexample, taxanes such as paclitaxel and docetaxel have been approved forthe chemotherapeutic treatment of several different varieties of tumors.As is known, paclitaxel is a naturally occurring taxane diterpenoidhaving the formula and numbering system for the taxane backbone asfollows:

Since the paclitaxel compound appears so promising as a chemotherapeuticagent, organic chemists have spent substantial time and resources inattempting to synthesize the paclitaxel molecule and other potent taxaneanalogs. The straightforward implementation of partial synthesis ofpaclitaxel, or other taxanes, requires convenient access to chiral,non-racemic side chains and derivatives, an abundant natural source ofbaccatin III or closely related diterpenoid substances, and an effectivemeans of joining the two. Perhaps the most direct synthesis ofpaclitaxel is the condensation of Baccatin III and 10-deacetylbaccatinIII of the formulae:

with the side chain:

However, the esterification of these two units is difficult because ofthe C-13 hydroxyl of both baccatin III and 10-deacetylbaccatin III arelocated within the sterically encumbered concave region of thehemispherical taxane skeleton.

Alternative methods of coupling the side chain to a taxane backbone toultimately produce paclitaxel have been disclosed in various patents.For example, U.S. Pat. No. 4,929,011 issued May 8, 1990 to Denis et al.entitled “Process for Preparing Taxol”, describes the semi-synthesis ofpaclitaxel from the condensation of a (2R,3S) side chain acid of thegeneral formula:

wherein P₁ is a hydroxyl protecting group with a taxane derivative ofthe general formula of:

wherein P₂ is a hydroxyl protecting group. The condensation product issubsequently processed to remove the P₁ and P₂ protecting groups. InDenis et al., the paclitaxel C-13 side chain, (2R,3S) 3-phenylisoserinederivative is protected with P₁ for coupling with protected BaccatinIII. The P₂ protecting group on the baccatin III backbone is, forexample, a trimethylsilyl or a trialkylsilyl radical.

An alternative semi-synthesis of paclitaxel is described in U.S. Pat.No. 5,770,745 to Swindell et al. Swindell et al. disclose semi-synthesisof paclitaxel from a baccatin III backbone by the condensation with aside chain having the general formula:

wherein R₁ is alkyl, olefinic or aromatic or PhCH₂ and P₁ is a hydroxylprotecting group.

Another technique for the semi-synthesis of paclitaxel is found in U.S.Pat. No. 5,750,737 to Sisti et al. In that patent, C7-CBZ baccatin IIIof the formula

is esterified with a C3-N-CBZ-C2-O-protected (2R,3S)-3-phenylisoserineside chain of the formula:

followed by deprotection, and 3N benzoylation to produce paclitaxel.

Another taxane compound that has been found to exhibit anti-tumoractivity is the compound known as “docetaxel.” This compound is alsosold under the trademark TAXOTERE®, the registration of which is ownedby Sanofi Aventis. Docetaxel has the formula as follows:

As may be seen in this formulation, docetaxel is similar to paclitaxelexcept for the inclusion of the t-butoxycarbonyl (Boc) group at the C3′nitrogen position of the phenylisoserine side chain and a free hydroxylgroup at the C10 position. Similar to paclitaxel, the synthesis ofdocetaxel is difficult due to the hindered C13 hydroxyl in the baccatinIII backbone, which is located within the concave region of thehemispherical taxane skeleton. Several syntheses of docetaxel andrelated compounds have been reported in the Journal of OrganicChemistry: 1986, 51, 46; 1990, 55, 1957; 1991, 56, 1681; 1991, 56, 6939;1992, 57, 4320; 1992, 57, 6387; and 993, 58, 255; also, U.S. Pat. No.5,015,744 issued May 14, 1991 to Holton describes such a synthesis.Additional techniques for the synthesis of docetaxel are discussed, forexample, in U.S. Pat. No. 5,688,977 to Sisti et al., U.S. Pat. No.6,107,497 to Sisti et al.

Due to the promising anti-tumor activity exhibited by both paclitaxeland docetaxel, further investigations have indicated that analogs andderivates within the taxane family may lead to new and better drugshaving improved properties such as increased biological activity,effectiveness against cancer cells that have developed multi-drugresistance (MDR), fewer or less serious side effects, improvedsolubility characteristics, better therapeutic profile and the like.

While the existing techniques for synthesizing paclitaxel and docetaxelcertainly have merit, there is still a need for improved chemicalprocesses that can produce this anti-cancer compound. Additionally,there is a need to provide new taxane compounds having improvedbiological activity for use in treating cancer and efficient protocolsof forming these compounds. Particularly, there is a need for a new sidechain that is easily and efficiently coupled to a taxane backbone forthe synthesis of important pharmaceutical compounds and intermediates.The present invention is directed to meeting these needs.

SUMMARY OF THE EXEMPLARY EMBODIMENTS

According to the present invention, then, methods are described for usein producing taxanes, taxane analogs, and derivatives thereof. Broadly,the method includes reacting a first compound of the general formula:

with a second compound of the general structure:

to give a third compound of the general formula:

wherein:

-   -   X is a halogen or OR₄;    -   X₁ is either R₁R₂; R₁P₁; R₂P₁; or P₁P₁    -   X₂ is a substituted or unsubstituted: alkyl, alkenyl, aryl,        aralkyl, or acyl;    -   X₃ is either R₁; R₂; or P₂;    -   R₁ and R₂ are independently H or substituted or unsubstituted:        alkyl, alkenyl, aryl, aralkyl, or acyl;    -   R₄ is H, a substituted or unsubstituted: alkyl, alkenyl, aryl,        aralkyl, acyl, alcoxy carbonyl or aryloxy carbonyl;    -   P₁ is an amine protecting group;    -   P₂ is a hydroxyl protecting group; and    -   E₁, E₂ and the carbon to which they are attached define a        tetracyclic taxane nucleus.        This third compound may take the more specific formula:

This third compound can be then converted to paclitaxel.

The second compound may have the a structure

-   -   Y₇ is R₇; P₃; or Z₇;    -   Y₉ is H; hydroxyl; a ketone; OR₉; P₄; or Z₉;    -   Y₁₀ is R₁₀; P₅; or Z₁₀;    -   Z₇ is P₃ and together with Y₉ forms a cyclic structure when Y₉        is P₄;    -   Z₉ is either:        -   P₄ and together with Y₇ forms a cyclic structure when Y₇ is            P₃; or P₅ and together with Y₁₀ forms a cyclic structure            when Y₁₀ is P₄;    -   Z₁₀ is P₅ and together with Y₉ forms a cyclic structure when Y₉        is P₄;    -   R₇ is H, substituted or unsubstituted: alkyl, alkenyl, aryl,        aralkyl, or acyl;    -   R₉ is a substituted or unsubstituted: alkyl, alkenyl, aryl,        aralkyl, or acyl;    -   R₁₀ is H, substituted or unsubstituted: alkyl, alkenyl, aryl,        aralkyl, or acyl;    -   P₃ is a hydroxyl protecting group;    -   P₄ is a hydroxyl protecting group; and    -   P₅ is a hydroxyl protecting group.        Here, if desired, X is a halogen; X₁ is R₁P₁; X₂ is Ph; X₃ is        P₂; Y₇ is P₃; Y₉ is a ketone; Y₁₀ is P₅; R₁ is H; P₁ is Boc; P₂        is BOM; P₃ is Cbz; and P₅ is Cbz. Alternatively, X is fluorine;        X₁ is R₁P₁; X₂ is Ph; X₃ is P₂; Y₇ is P₃; Y₉ is a ketone; Y₁₀ is        P₅; R₁ is H; P₁ is Cbz; P₂ is BOM; P₃ is Cbz; and P₅ is Cbz. In        another alternative, X is OR₄; X₁ is R₁P₁; X₂ is isobutyl; X₃ is        P₂; Y₇ is P₃; Y₉ is a ketone; Y₁₀ is P₅; R₁ is H; R₄ is H; P₁ is        Boc; P₂ is BOM; P₃ is Cbz; and P₅ is Cbz. In yet another        alternative, X is a halogen; X₂ is isobutyl; Y₇ is P₃; Y₉ is a        ketone; Y₁₀ is P₅; R₁ and R₂ are independently H or substituted        or unsubstituted: alkyl, alkenyl, aryl, aralkyl, or acyl; R₃ is        H; P₁ is Boc; P₂ is BOM; P₃ is Cbz; and P₅ is Cbz.

The third compound can have the formula:

Here, the method can include the step of converting this third compoundto docetaxel, paclitaxel, or a 7,9-acetal linked analog. This method mayinclude the step of deprotecting the third compound by substitutinghydrogen for P₁, P₂, P₃ and P₅ to form a fourth compound having theformula:

The third compound can also be deprotected by substituting hydrogen forP₃, and P₅ to form a fourth compound having the formula:

This fourth compound may be selectively acyalated at the C-10 positionto form a fifth compound having the formula:

The method contemplates converting this fifth compound into paclitaxel.

The third compound can also be oxidized to form a fourth compound of theformula:

This fourth compound can then be reduced to form a fifth compound of theformula:

This fifth compound may be acylated at the C-10 position to form a sixthcompound of the formula:

This sixth compound may further be deprotected by substituting hydrogenfor P₃ thereby to form a seventh compound of the formula:

The seventh compound can be converted into an eighth compound of theformula:

wherein R₁₂ and R₁₃ are independently H; substituted or unsubstituted:alkyl; alkenyl; aryl; aralkyl; or acyl. Here, R₁₂ and R₁₃ may each beindependently selected from the group consisting of:

According to some embodiments of the invention, the first compound is acyclic structure wherein the C-3 Nitrogen and the C-2 Oxygen are linkedby a common protecting group that includes R₁ and R₂ and that has theformula:

such that the third compound is a cyclic structure having the formula:

wherein R₃ is either H or P₁.The second compound again may have the a structure

-   -   Y₇ is R₇; P₃; or Z₇;    -   Y₉ is H; hydroxyl; a ketone; OR₉; P₄; or Z₉;    -   Y₁₀ is R₁₀; P₅; or Z₁₀;    -   Z₇ is P₃ and together with Y₉ forms a cyclic structure when Y₉        is P₄;    -   Z₉ is either:        -   P₄ and together with Y₇ forms a cyclic structure when Y₇ is            P₃; or P₅ and together with Y₁₀ forms a cyclic structure            when Y₁₀ is P₄;    -   Z₁₀ is P₅ and together with Y₉ forms a cyclic structure when Y₉        is P₄;    -   R₇ is H, substituted or unsubstituted: alkyl, alkenyl, aryl,        aralkyl, or acyl;    -   R₉ is a substituted or unsubstituted: alkyl, alkenyl, aryl,        aralkyl, or acyl;    -   R₁₀ is H, substituted or unsubstituted: alkyl, alkenyl, aryl,        aralkyl, or acyl;    -   P₃ is a hydroxyl protecting group;    -   P₄ is a hydroxyl protecting group; and    -   P₅ is a hydroxyl protecting group.        Here, if desired, X is a halogen; X₁ is R₁P₁; X₂ is Ph; X₃ is        P₂; Y₇ is P₃; Y₉ is a ketone; Y₁₀ is P₅; R₁ is H; P₁ is Boc; P₂        is BOM; P₃ is Cbz; and P₅ is Cbz. Alternatively, X is fluorine;        X₁ is R₁P₁; X₂ is Ph; X₃ is P₂; Y₇ is P₃; Y₉ is a ketone; Y₁₀ is        P₅; R₁ is H; P₁ is Cbz; P₂ is BOM; P₃ is Cbz; and P₅ is Cbz. In        another alternative, X is OR₄; X₁ is R₁P₁; X₂ is isobutyl; X₃ is        P₂; Y₇ is P₃; Y₉ is a ketone; Y₁₀ is P₅; R₁ is H; R₄ is H; P₁ is        Boc; P₂ is BOM; P₃ is Cbz; and P₅ is Cbz. In yet another        alternative, X is a halogen; X₂ is isobutyl; Y₇ is P₃; Y₉ is a        ketone; Y₁₀ is P₅; R₁ and R₂ are independently H or substituted        or unsubstituted: alkyl, alkenyl, aryl, aralkyl, or acyl; R₃ is        H; P₁ is Boc; P₂ is BOM; P₃ is Cbz; and P₅ is Cbz.

The present invention also discloses novel compounds produced in theforegoing methods. One such compound has the formula:

wherein:

-   -   X is a halogen or OR₄;    -   X₁ is either R₁, R₂; R₁P₁; R₂P₁; or P₁P₁    -   X₂ is a substituted or unsubstituted: alkyl, alkenyl, aryl,        aralkyl, or acyl;    -   X₃ is either R₁; R₂; or P₂;    -   R₁ and R₂ are independently H or substituted or unsubstituted:        alkyl, alkenyl, aryl, aralkyl, or acyl;    -   R₄ is a H, a substituted or unsubstituted: alkyl, alkenyl, aryl,        aralkyl, acyl, alcoxy carbonyl or aryloxy carbonyl;    -   P₁ is an amine protecting group;    -   P₂ is a hydroxyl protecting group.        More specifically, X can be selected from the group consisting        of chlorine, bromine, fluorine, and iodine.

This compound may be a cyclic structure wherein the C-3 Nitrogen and theC-2 Oxygen are linked by a common protecting group that includes R₁ andR₂ and that has the formula:

wherein R₃ is either H or P₁. X can again be selected from the groupconsisting of chlorine, bromine, fluorine, and iodine. If desired, X ischlorine; X₂ is isobutyl; R₁ and R₂ are independently H, or substitutedor unsubstituted: alkyl, alkenyl, aryl, aralkyl or acyl; R₃ is P₁; andP₁ is Boc. Here, the compound may take the structural formula:

Alternatively, X is R₄; X₂ is isobutyl; R₁ and R₂ are independently H,or substituted or unsubstituted: alkyl, alkenyl, aryl, aralkyl or acyl;R₃ is P₁ R₄ is trimethylacetyl; and P₁ is Boc. Accordingly, anothercyclic structure for this compound has the structural formula:

Where the compound has the general formula:

X can be OR₁₁; X₁ can be R₁P₁; X₂ can be isobutyl; X₃ can be P₂; R₁ isH; R₁₁ can be H; P₁ can be Boc; and P₂ can be BOM. Accordingly, thecompound can have the structural formula:

In the compound of the general formula, X can be fluorine; X₁ can beR₁P₁; X₂ can be isobutyl; X₃ can be P₂; R₁ is H; P₁ can be Boc; and P₂can be BOM. Accordingly, the compound can have the structural formula:

In the compound of the general formula, X can be OR₁₁; X₁ can be R₁P₁;X₂ can be Ph; X₃ can be P₂; R₁ can be H; R₁₁ can be H; P₁ can be Cbz;and P₂ can be BOM. Accordingly, the compound can have the structuralformula:

In the compound of the general formula, X can be fluorine; X₁ can beR₁P₁; X₂ can be Ph; X₃ can be P₂; R₁ can be H; P₁ can be Cbz; and P₂ canbe BOM. Accordingly, the compound can have the structural formula:

These and other aspects of the exemplary embodiments of the presentinvention will become more readily appreciated and understood from aconsideration of the following detailed description when taken togetherwith the accompanying drawings, in which:

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a diagram of a generalized coupling reaction Schemes 1a, 1band 1c according to the present invention;

FIG. 2 is a diagram of a generalized Scheme 2 for the synthesis ofdocetaxel from a coupled product formed by the coupling reactiongenerally shown in Scheme 1c;

FIG. 3 is a diagram of a generalized reaction Scheme 3 for the synthesisof paclitaxel from a coupled product formed by the coupling reactiongenerally shown in Scheme 1c;

FIG. 4 is a diagram of a generalized alternative reaction Scheme 4 forthe synthesis of paclitaxel from a coupled product formed by thecoupling reaction generally shown in Scheme 1c;

FIG. 5 is a diagram of a generalized reaction Scheme 5 for the synthesisof 9,10-α,α-7,9 acetal taxane analogs from a coupled product formed bythe coupling reaction generally shown in Scheme 1c;

FIG. 6 is a diagram of an exemplary synthesis of docetaxel according tothe present invention;

FIG. 6 a is a diagram of another exemplary synthesis of docetaxelaccording to the present invention;

FIG. 7 is a diagram of an exemplary synthesis of paclitaxel according tothe present invention;

FIG. 8 is a diagram of another exemplary synthesis of paclitaxelaccording to the present invention;

FIG. 9 is a diagram of an exemplary synthesis of 9,10-α,α-7,9 acetaltaxane analogs according to the present invention;

FIG. 10 is a diagram of a coupling reaction according to the generalscheme shown in FIG. 1 b;

FIG. 11 is a diagram of an alternative coupling reaction according tothe general scheme shown in FIG. 1 b;

FIG. 12 is a diagram of an exemplary synthesis of two side chaincompounds according to the present invention;

FIG. 13 is a diagram of an exemplary synthesis of an alternative sidechain compound according to the present invention; and

FIG. 14 is a diagram of an exemplary synthesis of yet another side chaincompound according to the present invention.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

As used above, and throughout the description of the invention, thefollowing terms, unless otherwise indicated, shall be understood to havethe following meanings:

Alkyl

The term “alkyl” as used herein alone or as part of another group,denotes optionally substituted, straight and branched chain saturatedhydrocarbon groups, preferably having 1 to 12 carbons in the normalchain.

The term “substituted alkyl” refers to an alkyl group substituted by,for example, one to four substituents, such as, halo, trifluoromethyl,trifluoromethoxy, hydroxy, alkoxy, cycloalkyoxy, heterocylooxy, oxo,alkanoyl, aryloxy, alkanoyloxy, amino, alkylamino, arylamino,aralkylamino, cycloalkylamino, heterocycloamino, disubstituted amines inwhich the 2 amino substituents are selected from alkyl, aryl or aralkyl,alkanoylamino, aroylamino, aralkanoylamino, substituted alkanoylamino,substituted arylamino, substituted aralkanoylamino, thiol, alkylthio,arylthio, aralkylthio, cycloalkylthio, heterocyclothio, alkylthiono,arylthiono, aralkylthiono, alkylsulfonyl, arylsulfonyl, aralkylsulfonyl,sulfonamido (e.g. SO.sub.2 NH.sub.2), substituted sulfonamido, nitro,cyano, carboxy, carbamyl (e.g. CONH.sub.2), substituted carbamyl (e.g.CONH alkyl, CONH aryl, CONH aralkyl or cases where there are twosubstituents on the nitrogen selected from alkyl, aryl or aralkyl),alkoxycarbonyl, aryl, substituted aryl, guanidino and heterocyclos, suchas, indolyl, imidazolyl, furyl, thienyl, thiazolyl, pyrrolidyl, pyridyl,pyrimidyl and the like. Where noted above where the substituent isfurther substituted it will be with halogen, alkyl, alkoxy, aryl oraralkyl.

Exemplary unsubstituted such groups include methyl, ethyl, propyl,isopropyl, n-butyl, t-butyl, isobutyl, pentyl, hexyl, isohexyl, heptyl,4,4-dimethylpentyl, octyl, 2,2,4-trimethylpentyl, nonyl, decyl, undecyl,dodecyl and the like. Exemplary substituents may include one or more ofthe following groups: halo, alkoxy, alkylthio, alkenyl, alkynyl, aryl,cycloalkyl, cycloalkenyl, hydroxy or protected hydroxy, carboxyl(—COOH), alkyloxycarbonyl, alkylcarbonyloxy, carbamoyl (NH.sub.2-CO—),amino (—NH.sub.2), mono- or dialkylamino, or thiol (—SH).

Alkenyl

The term “alkenyl”, as used herein alone or as part of another group,denotes such optionally substituted groups as described for alkyl,further containing at least one carbon to carbon double bond. Exemplarysubstituents include one or more alkyl groups as described above, and/orone or more groups described above as alkyl substituents.

Aryl

The term “aryl”, as used herein alone or as part of another group,denotes optionally substituted, homocyclic aromatic groups, preferablycontaining 1 or 2 rings and 6 to 12 ring carbons. Exemplaryunsubstituted such groups include phenyl, biphenyl, and naphthyl.Exemplary substituents include one or more, preferably three or fewer,nitro groups, alkyl groups as described above, and/or groups describedabove as alkyl substituents.

The term “substituted aryl” refers to an aryl group substituted by, forexample, one to four substituents such as alkyl; substituted alkyl,halo, trifluoromethoxy, trifluoromethyl, hydroxy, alkoxy, cycloalkyloxy,heterocyclooxy, alkanoyl, alkanoyloxy, amino, alkylamino, aralkylamino,cycloalkylamino, heterocycloamino, dialkylamino, alkanoylamino, thiol,alkylthio, cycloalkylthio, heterocyclothio, ureido, nitro, cyano,carboxy, carboxyalkyl, carbamyl, alkoxycarbonyl, alkylthiono,arylthiono, alkysulfonyl, sulfonamido, aryloxy and the like. Thesubstituent may be further substituted by halo, hydroxy, alkyl, alkoxy,aryl, substituted aryl, substituted alkyl or aralkyl.

Aralkyl

The term “aralkyl”, as used herein alone or as part of another grouprefers to alkyl groups as discussed above having an aryl substituent,such as benzyl or phenethyl, or naphthylpropyl, or an aryl as definedabove.

Acyl

The term “acyl”, as used herein alone or as part of another group,denotes the moiety formed by removal of the hydroxyl group from thegroup —COOH of an organic carboxylic acid. The acyl group canspecifically be PhCO or BnCO, for example.

Hydroxyl Protecting Group

The term “hydroxy (or hydroxyl) protecting group”, as used herein,denotes any group capable of protecting a free hydroxyl group which,subsequent to the reactions for which it is employed, may be removedwithout destroying the remainder of the molecule. Such groups, and thesynthesis thereof, may be found in “Protective Groups in OrganicSynthesis” by T. W. Greene and P. G. M. Wuts, Protective Groups inOrganic Synthesis, 3rd Edition, John Wiley & Sons, New York (1999), orFieser & Fieser. Exemplary hydroxyl protecting groups includemethoxymethyl, 1-ethoxyethyl, 1-methoxy-1-methylethyl, benzyloxymethyl,(.beta.-trimethylsilyl-ethoxy)methyl, tetrahydropyranyl,benzyloxycarbonyl, 2,2,2-tri-chloroethoxycarbonyl,t-butyl(diphenyl)silyl, trialkylsilyl, trichloromethoxycarbonyl, and2,2,2-trichloroethoxymethyl.

Amine Protecting Group

The term “amine protecting group” as used herein means an easilyremovable group which is known in the art to protect an amino groupagainst undesirable reaction during synthetic procedures and to beselectively removable. The use of amine protecting groups is well knownin the art for protecting groups against undesirable reactions during asynthetic procedure and many such protecting groups are known, forexample, T. W. Greene and P. G. M. Wuts, Protective Groups in OrganicSynthesis, 3rd Edition, John Wiley & Sons, New York (1999), incorporatedherein by reference. Exemplary amine protecting groups are acyl,including formyl, acetyl, chloroacetyl, trichloroacetyl,o-nitrophenylacetyl, o-nitrophenoxyacetyl, trifluoroacetyl, acetoacetyl,4-chlorobutyryl, isobutyryl, o-nitrocinnamoyl, picolinoyl,acylisothiocyanate, aminocaproyl, benzoyl and the like, and acyloxyincluding methoxycarbonyl, 9-fluorenylmethoxycarbonyl,2,2,2-trifluoroethoxycarbonyl, 2-trimethylsilylethxoycarbonyl,vinyloxycarbonyl, allyloxycarbonyl, t-butyloxycarbonyl (BOC),1,1-dimethylpropynyloxycarbonyl, benzyloxycarbonyl (CBZ),p-nitrobenzyloxycarbony, 2,4-dichlorobenzyloxycarbonyl, and the like.

Halogen

The term “halogen” as used herein alone or as part of another group,denotes chlorine, bromine, fluorine, and iodine.

Taxane

The term “taxane”, as used herein, denotes compounds containing a taxanemoiety as described above. The term “C-13 acyloxy sidechain-bearingtaxane”, as used herein, denotes compounds containing a taxane moiety asdescribed above, further containing an acyloxy sidechain directly bondedto said moiety at C-13 through the oxygen of the oxy group of theacyloxy substituent.

The exemplary embodiments of the present invention generally relate tothe synthesis of anti-tumor compounds including, for example, docetaxel,paclitaxel, and taxane analogs having a stereochemistry at the C-9 andC-10 OH positions. One aspect of the present invention is a novel anduseful side chain for attachment to a taxane backbone for the synthesisof these anti-tumor compounds. Another aspect of the present inventionincludes the synthesis of desired anti-tumor compounds subsequent to theattachment of the novel side chain to the taxane backbone.

Turning first, then, to FIG. 1, (Schemes 1a, b and c), this new sidechain is generally represented as compound A. As shown, side chain A maybe attached at the C13 position of taxane backbone B, thereby to formcoupled product C. Coupled product C may then, if desired, undergofurther synthesis to produce the anti-tumor compounds of interest, suchas generally shown in FIGS. 2-5 (Schemes 2-5), which will be discussedin more detail below.

Broadly, side chain A may have the formula wherein:

-   -   X is a halogen or OR₄;    -   X₁ is either R₁R₂; R₁P₁; R₂P₁; or P₁P₁    -   X₂ is substituted or unsubstituted: alkyl, alkenyl, aryl,        aralkyl, or acyl;    -   X₃ is either R₁; R₂; or P₂;    -   R₁ and R₂ are independently H or substituted or unsubstituted:        alkyl, alkenyl, aryl, aralkyl, or acyl;    -   R₄ is a H, a substituted or unsubstituted: alkyl, alkenyl, aryl,        aralkyl, acyl, alkoxy carbonyl or aryloxy carbonyl    -   P₁ is an amine protecting group;    -   P₂ is a hydroxyl protecting group;

Side chain A can also have a structure as follows, when 2-O and 3-N arelinked with a common protecting group such as in a cyclic acetal:

wherein, R₃ is either H or P₁

Some examples of side chain A have the following exemplary structuralformulas:

Broadly taxane backbone B may have the formula wherein:

E1, E2 and the carbon to which they are attached define a tetracyclictaxane nucleusTaxane backbone B may have the following general structural formulawherein:

-   -   Y₇ is R₇; P₃; or Z₇;    -   Y₉ is H; hydroxyl; a ketone; OR₉; P₄; or Z₉;    -   Y₁₀ is R₁₀; P₅; or Z₁₀;    -   Z₇ is P₃ and together with Y₉ forms a cyclic structure when Y₉        is P₄;    -   Z₉ is either:        -   P₄ and together with Y₇ forms a cyclic structure when Y₇ is            P₃; or P₅ and together with Y₁₀ forms a cyclic structure            when Y₁₀ is P₄;    -   Z₁₀ is P₅ and together with Y₉ forms a cyclic structure when Y₉        is P₄;    -   R₇ is H, substituted or unsubstituted: alkyl, alkenyl, aryl,        aralkyl, or acyl;    -   R₉ is a substituted or unsubstituted: alkyl, alkenyl, aryl,        aralkyl, or acyl;    -   R₁₀ is H, substituted or unsubstituted: alkyl, alkenyl, aryl,        aralkyl, or acyl;    -   P₃ is a hydroxyl protecting group;    -   P₄ is a hydroxyl protecting group; and    -   P₅ is a hydroxyl protecting group.        When side chain A is coupled with taxane backbone B, coupled        product C has the following broad structure;

Wherein: X₁, X₂, X₃, E₁ and E₂ are as above

When 2-O and 3-N are linked with a common protecting group; wherein R₁and R₂ are as above.Some examples of coupled products have the following exemplarystructural formulas:

Set forth below are general examples, followed by specific examples, ofboth the synthesis of coupled product C as well as the subsequentanti-tumor compounds and intermediates formed thereby. It should beappreciated however, that coupled product C could be useful tosynthesize other useful compounds.

I. Synthesis of Docetaxel

Docetaxel may be formed in a number of ways according to the presentinvention, a general example of which is shown in FIG. 2 (Scheme 2). Asshown, coupled product D, which is formed by the attachment of a sidechain to a taxane backbone as generally shown in Scheme 1c, undergoesvarious transformations to form docetaxel F. More particularly, coupledproduct D is first deprotected at the C7, C10, C3′N and C2′ to form afirst intermediate E. Subsequently, the Boc group is attached to theN—C3′ site to form docetaxel F.

Such a process is exemplified in FIG. 6. As shown, side chain of Formula1 (wherein: X is fluorine; X₁ is R₁P₁; X₂ is Ph; X₃ is P₂; R₁ is H; P₁is Cbz; and P₂ is BOM) is coupled to taxane backbone of Formula 2, whichis C7, C10 di-Cbz 10-deacetylbaccatin III (wherein: Y₇ is P₃; Y₉ is aketone; Y₁₀ is P₅; P₃ and P₅ are each Cbz) to form coupled product ofFormula 3.

A solution of the acid fluoride, Formula 1, in methylene chloride wasadded via a syringe, to a solution of C7, C10 di-Cbz 10-deacetylbaccatinIII, Formula 2, (5.6 g) and 4-PP (1.55 g) in anhydrous methylenechloride (40 mL), at room temperature and an atmosphere of nitrogen. Thereaction was stirred at room temperature for four hours, then, dilutedwith methylene chloride (75 mL), washed with water (2×50 mL), brine(1×30 mL), dried over sodium sulphate and rotostripped. The crudeproduct was purified on a silica plug, eluting with a gradient eluentinvolving isopropyl acetate and heptanes. The pure fractions were pooledand rotostripped to give the cleaned-up coupled ester as a foamy solid.The solid was suspended in methanol (200 mL) and stirred vigorously forfive hours at room temperature. The white solids were filtered, washedwith minimum methanol and dried in the vacuum oven to afford the coupledester, Formula 3, as a white solid (7.3 g, 86%).

A solution of HCl (1.7 mL) in tetrahydrofuran (25 mL) and water (1.7 mL)and Pd/C (10 wt % palladium, 4.0 g) was added to a solution of coupledester, Formula 3, (5.0 g) in tetrahydrofuran (75 mL). The reaction wasstirred vigorously overnight under an atmosphere of hydrogen. Thereaction mixture was then filtered through a bed of celite (15 g),washed with tetrahydrofuran (2×75 mL) and the filtrate was transferredto a round bottomed flask and used as such for the next reaction.

To this tetrahydrofuran solution was added di-tert-butyldicarbonate (2.0g) and triethylamine (3.5 mL) at room temperature under nitrogenatmosphere and stirred overnight. The reaction mixture was then filteredthrough a bed of celite and washed with isopropyl acetate (3×75 mL). Theorganic layer was then washed with 0.1N HCl solution (till neutral pH),water (2×50 mL), dried and rotostripped to afford docetaxel (4.26 g),Formula 5, which is then purified by column chromatography.

II. Synthesis of Paclitaxel

Two general syntheses of paclitaxel are shown, the first in FIG. 3(Scheme 3) and an alternative in FIG. 4 (Scheme 4). Turning first toFIG. 3, coupled product D is, as described above, generally formed bythe attachment of a side chain to a taxane backbone as generally shownin Scheme 1c. The protecting groups are then removed at C7 and C10 andthe C3′ nitrogen side chain site to produce intermediate compound H.Thereafter, intermediate compound H is acylated at the C3′ nitrogen,yielding intermediate compound I, and then selectively acylated at C10site to yield intermediate compound J. Compound J is then deprotected atthe C2′ site to produce paclitaxel K.

The general process shown in Scheme 3 may be further exemplified in FIG.7. Here again, coupled ester of Formula 3 is formed by the coupling ofside chain of Formula 1 to C7, C10 di-Cbz 10-deacetylbaccatin III ofFormula 2 as described above with reference to FIG. 6. Thetransformation of coupled ester of Formula 3, through intermediatecompounds of Formulas 6, 7, and 8, to arrive at paclitaxel of Formula 9is described in U.S. Pat. No. 6,066,749 and U.S. Pat. No. 6,448,417,which are both herein incorporated by reference.

An alternative generalized scheme for producing paclitaxel is shown inFIG. 4 (Scheme 4), beginning with coupled product L, which can be formedby the generalized reaction shown in Scheme 1c. Coupled product L isfirst deprotected at C7 and the N—C3′ site and the benzoyl group isplaced onto the nitrogen to yield intermediate compound J. The benzoylgroup is then placed onto the nitrogen and deprotection at C2′ yieldspaclitaxel K.

The process in Scheme 4 is exemplified in FIG. 8. As shown, side chainof Formula 1 (wherein: X is fluorine; X₁ is R₁P₁; X₂ is Ph; X₃ is P₂; R₁is H; P₁ is Cbz; and P₂ is BOM) is coupled to taxane backbone of Formula10, which is C7-Cbz baccatin III, Formula 10 (wherein: Y₇ is R₇; Y₉ is aketone; Y₁₀ is P₅; R₁₀ is AcO; P₃ is Cbz) to form coupled product ofFormula 11.

A solution of the acid fluoride, Formula 1, in methylene chloride wasadded through a syringe to a solution of C7-Cbz baccatin III, Formula10, (3.93 g) and 4-PP (1.62 g) in anhydrous methylene chloride (40 mL)at room temperature the reaction was stirred under nitrogen atmospherefor four hours, diluted with methylene chloride (75 mL), washed withsaturated ammonium chloride solution (1×50 mL), water (2×50 mL), brine(1×30 mL), dried over sodium sulphate and rotostripped to afford a foamysolid (˜8.9 g). The solid was suspended in methanol (30 mL) and stirredvigorously for five hours at room temperature. The white solids werefiltered, washed with minimum methanol and dried in the vacuum oven toafford the coupled ester, Formula 11, as a white solid (4.9 g, 79%yield, 94.5% by area). The transformation of coupled ester of Formula 11to the resultant paclitaxel of Formula 9 is described in U.S. Pat. No.5,750,737 which is herein incorporated by reference.

III. Synthesis of 7,9-Acetal Linked Analogs

A general synthesis of 7,9-acetal linked analogs is shown in FIG. 5(Scheme 5). Coupled product D, which is generally formed by a processaccording to Scheme 1c, and is synthesized to yield 7,9-acetal linkedanalog R. In general, coupled product D is deprotected at C10 to formintermediate product M, which is then oxidized to form intermediatecompound N. Reduction of intermediate compound N yields intermediatecompound O, which after selective acylation at C10 yields intermediatecompound P. Intermediate compound P is then deprotected at both the C7and the C2′ sites to afford intermediate compound Q, which wasthereafter converted to 7,9-acetal linked analog R.

Such a process is exemplified in FIG. 9. As shown, side chain of Formula31 (wherein: X is OR₄; X₁ is R₁P₁; X₂ is isobutyl; X₃ is P₂; R₁ is H; R₄is H; PI is Boc; and P₂ is BOM) is coupled to C7, C10 di-Cbz10-deacetylbaccatin III, Formula 2 to yield coupled ester of Formula 13.Here, the side chain of Formula 31, (38 g, 99.6 mmol) was dissolved intoluene to a known concentration (0.09524 g/mL). This solution was addedto Formula 2 (54.0 g, 66.4 mmol). The solution was heated in awarm-water bath and DMAP (8.13 g, 66.4 mmol) and DCC (25.28 g, 119.6mmol) in toluene (540 mL) were added to the warm reaction mixture. Whilemaintaining the temperature at about 51° C., the reaction wascontinually stirred and sampled periodically for HPLC. After 3 hours,additional DCC (13.0 g) in toluene (140 mL) was added.

After approximately 25 hours, MTBE (450 mL) was added and the reactionmixture was filtered through a pad of silica gel, washed with MTBEfollowed by EtOAc, and concentrated to give 61.8 g oil. The silica waswashed again with EtOAc and the second pool was concentrated to 50 mLand allowed to sit. The following day the second pool had started tocrystallize. It was filtered and the solids were washed with 1:1heptane/IPAc and dried under vacuum at 40° C. to give a solid of Formula13.

Next, Formula 13 was deprotected at both the C7 and C10 positions andthe C2′ side chain position to give Formula 14. A Parr reactor wascharged with a solution of Formula 13 (68.0 g, 57.823 mmol) in THF (1.02L). The reactor was flushed with nitrogen and a solution of HCl (24.75mL) in THF (340 mL) was added followed by Pd/C (10%, wet type containing50% water) (108.8 g). The reactor was evacuated and flushed withnitrogen repeatedly (thrice), followed by hydrogen (twice). The contentsof the reactor were then stirred vigorously, overnight, at RT underhydrogen pressure (40 psi). The reaction was judged complete HPLCanalysis. The contents of the reactor were then filtered through a padof celite (celite 521, 100 g) and washed with THF. The green filtratewas neutralized with TEA (20 mL) to pH 7.5 and evaporated in-vacuo. Theresidue was dissolved in isopropyl acetate and washed with water. Theemulsion formed, if any, was filtered through filter paper under suctionand the filtrate was washed with saturated ammonium chloride solutionand brine. The filtrate was then dried over anhydrous sodium sulfate andpassed through a silica pad, eluting with isopropyl acetate. Thesolvents were rotostripped and the residue triturated with heptanes(twice) and rotostripped to afford the crude product which was purifiedon a silica column to afford clean Formula 14 as a white solid (40.64g).

Formula 14 was then converted to Formula 15. Formula 14 (41.37 g, 52.5mmol) was dissolved in DCM (500 mL) at room temperature. TEA (35 mL)followed by DMAP (1.284 g) and TES-CI (˜30 mL, 3.5 eq) were added to thesolution and stirred. Additional TES-CI (15 mL) and TEA (20 mL) wereadded, and after 6 hours HPLC analysis indicated completion of thereaction.

The reaction was then quenched by the addition of EtOH (25 mL). Thesolvent was stripped to half the volume on the rotavapor and the residuewas purified on a silica gel flash column eluting with 8:2 heptane/IPAc.Fractions containing the product were pooled and concentrated to giveFormula 15 as a foam.

Formula 15 was then oxidized to form Formula 16. A solution of Formula15 (24.45 g, 24.0 mmol) and 4-methyl morpholine N-oxide (10.1 g, 84mmol) in DCM (340 mL) was dried over Na₂SO₄ for 1 hour and then filteredthrough 24 cm fluted filter paper into a 2 L 3-N round bottom flask. TheNa₂SO₄ solids were washed with DCM (100 mL) into the flask. Molecularsieves (6.1 g, 15% wt/wt) were added to the stirring solution. TPAP(1.38 g) was added and the reaction was allowed to stir under a N₂atmosphere. Samples were taken periodically for HPLC. Additional TPAP(0.62 g) was added after 2 hours and again (0.8 g) after 15 hours. Thereaction mixture was applied to a pad of silica gel (86 g), wet with 8:2heptane/IPAc and eluted with IPAc. The fractions were collected, pooledand concentrated to a foamy solid product of Formula 16 which was thenrecrystallized from methanol.

Formula 16 was then reduced to form Formula 17. NaBH₄ (365 mg, 6 eq) wasadded to a stirred solution of Formula 16 (1.6 g) in EtOH (19 mL) andMeOH (6.5 mL) at 0° c. After 1 hour, the reaction mixture was removedfrom the ice-water bath and at 2 hours, the reaction was sampled forHPLC, which indicated the reaction had gone to completion. The reactionmixture was cooled in an ice-water bath and quenched with a solution ofNH₄OAc in MeOH (15 mL) followed by the addition of IPAc (50 mL) and H₂O(20 mL). The organic layer was separated and washed with water (20 mL)and brine (10 mL). It was dried over Na₂SO₄ and concentrated on therotovap. It was placed in the vacuum oven to give product of Formula 17as a foam.

Formula 17 was next acylated to form Formula 18. TEA (5.8 mL, 41.5mmol), Ac₂O (2.62 mL, 27.7 mmol) and DMAP (724 mg, 5.5 mmol) were addedto a solution of Formula 17 (14.1 g. 13.84 mmol) in DCM (50 mL). Thereaction was stirred and sampled for HPLC periodically. At 19 hours,HPLC indicated the reaction had gone to completion. The reaction mixturewas diluted with IPAc (300 mL) and poured into 5% NaHCO₃ (100 ml). Theorganic layer was then separated and washed with water (100 mL),saturated NH₄Cl (2×100 mL), water (3×50 mL) and brine (50 mL). Thesolution was dried over Na₂SO₄ and concentrated to give a foam productof Formula 18.

Next, Formula 18 was converted to a compound of Formula 19. To asolution of Formula 18 (3.0 g, 2.829 mmol) in DCM (24 mL) and MeOH (6mL), at room temperature, CSA (0.0394 g, 0.17 mmol) was added. Thereaction was judged complete at four hours by LCMS analysis. 5% NaHCO₃(15 mL) was added to the reaction mixture and shaken vigorously in aseparatory funnel and the layers were separated. The organic layer waswashed with brine, dried over Na₂SO₄, and concentrated. MTBE (3×25 mL)was added and the reaction mixture was concentrated to dryness aftereach addition to finally give 3.7068 g foam. The foam was dissolved inMTBE (10 mL) and stirred. Heptane (50 mL) was slowly added to thereaction solution and solids began to form immediately. The solids werevacuum filtered and rinsed with heptane (70 mL). The solids werecollected and dried in a vacuum oven at 40° C. to give Formula 19.

Formula 19 was then converted to Formula 20. A solution of Formula 19(2.1 g, 2.52 mmol) in DCM (10.5 mL) was stirred at room temperature.Next, 3,3-dimethoxy-1-propene (2.03 g, 17.7 mmol) followed by CSA (0.035g, 0.15 mmol) were added to the solution. After the solution was stirredfor 3.5 hours, LCMS indicated the reaction had gone to completion. Thereaction was diluted with DCM (25 mL) and transferred to a separatoryfunnel and washed with 55 mL 5% NaHCO₃ solution. The layers wereseparated and the aqueous layer was washed with DCM (25 mL). The twoorganic layers were combined, washed with brine, dried over Na₂SO₄ andconcentrated. The crude product was purified by silica gel flashchromatography eluting with 50:50 MTBE/heptane. The fractions werecollected, pooled, concentrated and dried in a vacuum oven at 50° C. togive product of Formula 20.

IV. Alternative Side Chain Coupling Reactions

Additional specific examples of the coupling reaction generally shown inFIG. 1 (Scheme 1a, b and c) are shown in FIGS. 9, 10 and 11. Withrespect to FIG. 10, side chain of Formula 21 (wherein: X is chlorine;2-O and 3-N are linked with a common protecting group; R₃ is P₁; R₁ andR₂ are H and substituted aryl; X₂ is isobutyl; P₁ is Boc) is coupled toC7, C10 di-Cbz 10-deacetylbaccatin III (wherein: Y₇ is P₃; Y₉ is aketone; Y₁₀ is P₅; P₃ and P₅ are each Cbz) Formula 2 to form coupledproduct of Formula 22.

40 g of anhydrous sodium sulfate was added to a solution of C7, C10di-Cbz 10-deacetylbaccatin III 5.00 g (6.15 mmol, 1.0 eq), Formula 2, in150 mL dichloromethane. After three hours, the mixture was filtered andthe filtrate was concentrated under reduced pressure. The C7, C10 di-Cbz10-deacetylbaccatin III, Formula 2, was re-dissolved in anhydrousdichloromethane (50 mL) at ambient temperature, and subsequently, 2.25 g(18.4 mmol, 3.0 eq) 99% 4-DMAP was added and the solution was placedunder an inert atmosphere of nitrogen. A solution of side chain, Formula21, in dichloromethane, was added to the resulting solution at ambienttemperature. The progress of the reaction was monitored by HPLC (areaction aliquot was quenched into methanol). After stirring overnight,the solution was concentrated to dryness and the crude product was flashchromatographed over silica gel using 2/1 (v/v) EtOAc-heptane as theeluent. Appropriate fractions were pooled and concentrated in vacuo toconstant weight to afford 7.31 g (98.7%) coupled product, Formula 22 asan off-white solid; 84.5 AP (230 nm).

Turning now to FIG. 11, side chain of Formula 23 (wherein: X is OR₄; 2-Oand 3-N are linked with a common protecting group; R₃ is P1; R₁ and R₂are H and substituted aryl; X₂ is isobutyl; R₄ is t-butyl carbonyl; andP₁ is Boc.) is coupled to C7, C10 di-Cbz 10-deacetylbaccatin III,Formula 2, which also forms coupled product of Formula 22 (discussedabove with respect to FIG. 10).

A solution of Formula 23 (5.5 g, 13.47 mmol) in THF (30 mL) was cooledto 0° C. with an ice-water bath and 0.20 mL (1.8 mmol) 99%4-methylmorpholine and 0.22 mL (1.8 mmol, 0.2 eq) 99%trimethylacetylchloride (pivaloyl chloride) were added. The reaction wasstirred at ambient temperature for one hour. To this reaction mixturewas then added a solution containing 1.76 g (14.4 mmol, 1.60 eq) 99%4-DMAP and 7.30 g (8.98 mmol, 1.0 eq) of C7, C10 di-Cbz10-deacetylbaccatin III, Formula 2, and the reaction was gently heatedunder reflux for about sixteen (16) hours under an inert atmosphere ofnitrogen. After cooling to ambient temperature, the reaction wasconcentrated to dryness and reconstituted in EtOAc (60 mL). Afterstirring for about ten minutes, solids were removed by filtration. Thefiltrate was washed with saturated sodium bicarbonate solution (60 mL),water (60 mL) and brine (60 mL). The organic phase was concentrated todryness to afford 14.52 g (>100%) crude coupled product, Formula 22.This crude material was dissolved into five volumes of MeOH and addeddropwise (slowly) into water (10 volumes) with good stirring. The solidswere filtered and dried to constant weight in vacuo at about 45° C. toyield 10.84 g (100%) coupled product, Formula 22, as a white solid; 74.2AP (230 nm).

Another specific example of coupling as in FIG. 9, Formula 12 (wherein:X is F; X₁ is R₁P₁; X₂ is isobutyl; X₃ is P₂; R₁ is H; P₁ is Boc; and P₂is BOM) is coupled to C7, C10 di-Cbz 10-deacetylbaccatin III, Formula 2to yield coupled ester of Formula 13.

Coupling of side chain acid, Formula 12 to alcohol Formula 2:

A solution of acid fluoride (Formula 12) (28.30 gm, 73.81 mmol) in 60 mlof DCM was added dropwise to a stirring solution of alcohol (Formula 2)(50.0 gm, 61.51 mmols) and 4-pyrrolidino pyridine (11.39 gm, 76.89 gm)DCM (250 mL) at room temperature under nitrogen. TLC and LC-MS analysisafter 13 hours revealed complete consumption of alcohol (formula 2) withtraces of acid fluoride remaining and formation of desired coupled ester(Formula 13). The reaction mixture was diluted with 100 ml of DCM andtransferred to a separatory funnel. The DCM layer was washed with water(2×100 ml), brine (100 ml), dried over sodium sulfate (80 gm) androtostripped to afford a solid (81.80 gm). The crude product waspurified on a silica plug, eluting with IPAC. The pure fractions werepooled and the solvents were evaporated to afford the coupled ester(Formula 13) (78.4 gm) as an off white solid after repeated washes withheptanes.

V. Formation of Side Chains

As described above, one of the aspects of the present invention is thenovel side chain, generally shown as compound A in Scheme 1a and b (FIG.1). Thus far, several specific coupling reactions involving various sidechains contemplated by the present invention have been described abovewith reference to FIGS. 6-11 above. Now, the formation of theseparticular novel side chains can be described with reference first toFIG. 12.

A. Synthesis of Side Chain—Formula 1 and Formula 12

FIG. 12 shows an exemplary process for producing both side chains ofFormula 1 and Formula 12.

Formula 26 (prepared as described in J. Org. Chem. 2001, 66, 3330-3337)was converted to formula 27.

Formula 26 (12.1 g, 49.79 mmol) was dissolved in 120 ml of toluene andadded to a 250 ml 3-necked flask fitted with a reflux condenser undernitrogen and stirred. TEA (17.34 mL, 124.48 mmol) was added followed byBOM-CI (13.6 g, 87.13 mmol) as the bath was heated to 120° C. After 2.5hours TLC indicated all of starting material had converted to a fasterspot. The reaction was cooled and poured into a separating funnel anddiluted with 300 ml EtOAc and washed with 200 ml of 1N HCl. The layerswere separated, washed with 300 ml of 5% NaHCO₃, 200 ml brine, driedover Na₂SO₄, filtered and concentrated. Crude product formula 27 used assuch in the next step.

Formula 27 (2.0 g, 5.5 mmol) was dissolved in THF (100 mL), chilled to5° C. and stirred vigorously. In 100 mL water with stirring NaIO₄ (2.35g, 11.0 mmol) and NMO (1.29 g, 11.0 mmol) were dissolved, which wasslowly added to the chilled THF solution. Lastly, OsO₄ (0.035 g, 0.025eq.) was added. After 6 hours the reaction was complete as indicated byTLC. The THF was stripped under vacuum, sodium thiosulfate solution wasadded and the mixture was shaken. The resulting aqueous mixture wasextracted with EtOAc (3×50 mL). The organic extract was washed withbrine, dried over Na₂SO₄, filtered and then concentrated to oil. Thealdehyde product formula 28 was used directly in the next step withoutpurification.

Formula 28 (3.44 g, 9.42 mmol) was dissolved in 70 ml of tBuOH and 20 mLwater was added and stirring was commenced under nitrogen. Na₂HPO₄(2.324 g, 16.96 mmol) and 2-methyl 2-butene (18.75 mL, 169.6 mmol) wasadded and the solution cooled on an ice water bath. Sodium Chlorite(2.03 g, 22.62 mmol) was added over a period of two minutes and the icebath removed and the solution stirred and allowed to rise to roomtemperature and stir for one hour. TLC indicated the reaction had goneto completion. 15 mL of Na₂S₂O₃ was added slowly followed by 50 mL ofEtOAc. The organic layer was separated and aqueous layer back extractedwith 50 mL EtOAc, dried over Na₂SO₄, filtered and then concentrated.Purification by silica gel chromatography gave 2.8 g of acid formula 12.

If desired, side chain of Formula 31 can then be converted to side chainof Formula 12 as shown. By one method, Formula 31 to Formula 12 (acid toacid fluoride) is as follows:

Pyridine (10.7 mL, 131.2 mmol) was added dropwise to a solution of sidechain acid (Formula 31) (40.0 g, 104.99 mmol) in dichloromethane (200ml) at room temperature under an atmosphere of nitrogen. The reactionwas then cooled to 10° C. and DAST (Diethylamino sulfur trifluoride)(150.1 mL, 115.48 mmol) was added via a syringe at a rate that thereaction temperature was maintained below −5° C. Stirring was continuedfor about 2 hours when TLC indicated the reaction was complete. Thereaction was quenched at −10° C. by the addition of ice cold water (20mL).

The mixture was transferred to a separatory funnel and the methylenechloride layer was separated washed with 150 mL of cold water and 100 mlof brine solution. The organic layer was dried over 40 gm of Sodiumsulfate and rotostripped to afford the crude acid fluoride as an oil.The crude product was purified on a silica plug, eluting with 25% IPACin heptanes to afford the clean product Formula 12 as an oil (38.8 g,96.5%) after the solvents were rotostripped.

For this conversion and for the conversions of other acids to acidfluorides, reagents such as Deoxoflour, cyanuric fluoride and TFFH canalso be used in addition to the DAST method shown here. Formula 1 wasalso synthesized according to the above described fluorination methods.

B. Synthesis of Side Chain—Formula 21 and Formula 23

Turning now to FIGS. 13 and 14, side chains, Formula 21 and 23, can bothbe formed from the side chain, Formula 29. Synthesis of formula 29 isdescribed in WO 01/02407 A2 to Bombardelli et al., which is incorporatedherein by reference. As shown in FIG. 13. side chain Formula 29 can beconverted to acid chloride side chain, Formula 21. First, a solution wasprepared containing 7.96 g (18.4 mmol, 3.0 eq) side chain, Formula 29and 2.25 g (18.4 mmol) 99% 4-DMAP in anhydrous dichloromethane (80 mL).To this solution, 1.70 mL (19.1 mmol, 3.1 eq) 98% oxalyl chloride (neat)was added at ambient temperature under an inert atmosphere of nitrogen.The resulting mixture was stirred at ambient temperature for about 30minutes, 98% oxalyl chloride (0.5 mL) was added and the mixture wasstirred for an additional 30 minutes. HPLC analysis indicated conversionto acid chloride side chain, Formula 21 was complete (a reaction aliquotwas quenched into methanol and analyzed as methyl ester). The mixturewas filtered and the solids were washed with anhydrous dichloromethane(30 mL). The filtrate was concentrated under reduced pressure and theoil was further concentrated in vacuo under high vacuum for 25 minutes.The resulting oil was re-dissolved in anhydrous dichloromethane (30 mL)thereby producing a solution containing acid chloride side chain ofFormula 21.

Turning to FIG. 14, side chain of Formula 23 can be synthesized fromside chain of Formula 29.

A solution containing 55.00 g (127.5 mmol) of side chain, Formula 29, indichloromethane (550 mL) was washed with cold (0-5° C.) 2N aqueous HClsolution (2×460 mL). The organic phase was washed with 12.5 wt % sodiumchloride solution (2×460 mL), dried over anhydrous sodium sulfate,filtered and concentrated in vacuo to constant weight to afford 50.35 g(96.5%) free acid, Formula 30.

To a 0-5° C. solution of 5.51 g (13.5 mmol) free acid Formula 30 inanhydrous THF (50 mL) under an inert atmosphere of nitrogen was added1.78 mL (16.2 mmol) 99% 4-methylmorpholine and 1.99 mL (16.2 mmol) 99%trimethylacetyl chloride. The progress of the reaction was monitored byHPLC (a reaction aliquot was quenched into MeOH). After one hour, 0.20mL (1.8 mmol, 0.2 eq) 99% 4-methylmorpholine and 0.22 mL (1.8 mmol, 0.2eq) 99% trimethylacetyl chloride were added. After an additional 30minutes at 0-5° C., the conversion to the mixed anhydride side chain,Formula 23 was complete.

1. A method for use in producing taxanes, taxane analogs, andderivatives thereof, comprising the step of reacting a first compound ofthe general formula:

with a second compound of the general structure:

to give a third compound of the general formula:

wherein: X is a halogen or OR₄; X₁ is either R₁R₂; R₁P₁; R₂P₁; or P₁P₁X₂ is a substituted or unsubstituted: alkyl, alkenyl, aryl, aralkyl, oracyl; X₃ is either R₁; R₂; or P₂; R₁ and R₂ are independently H orsubstituted or unsubstituted: alkyl alkenyl, aryl, aralkyl, or acyl; R₄is a substituted or unsubstituted: alkenyl, aryl, aralkyl, acyl, alkoxycarbonyl or aryloxy carbonyl, aroyl or alkali metal; P₁ is an amineprotecting group; P₂ is a hydroxyl protecting group; and E₁, E₂ and thecarbon to which they are attached define a tetracyclic taxane nucleus.2. A method according to claim 1 wherein the second compound has astructure

Y₇ is R₇; P₃; or Z₇; Y₉ is H; hydroxyl; a ketone; OR₉; P₄; or Z₉; Y₁₀ isR₁₀; P₅; or Z₁₀; Z₇ is P₃ and together with Y₉ forms a cyclic structurewhen Y₉ is P₄; Z₉ is either: P₄ and together with Y₇ forms a cyclicstructure when Y₇ is P₃; or P₅ and together with Y₁₀ forms a cyclicstructure when Y₁₀ is P₄; Z₁₀ is P₅ and together with Y₉ forms a cyclicstructure when Y₉ is P₄; R₇ is H, substituted or unsubstituted: alkyl,alkenyl, aryl, aralkyl, or acyl; R₉ is a substituted or unsubstituted:alkyl, alkenyl, aryl, aralkyl, or acyl; R₁₀ is H, substituted orunsubstituted: alkyl, alkenyl, aryl, aralkyl, or acyl; P₃ is a hydroxylprotecting group; P₄ is a hydroxyl protecting group; and P₅ is ahydroxyl protecting group.
 3. A method according to claim 2 wherein X isa halogen; X₁ is R₁P₁; X₂ is Ph; X₃ is P₂; Y₇ is P₃; Y₉ is a ketone; Y₁₀is P₅; R₁ is H; P₁ is Boc; P₂ is BOM; P₃ is Cbz; and P₅ is Cbz.
 4. Amethod according to claim 2 wherein X is fluorine; X₁ is R₁P₁; X₂ is Ph;X₃ is P₂; Y₇ is P₃; Y₉ is a ketone; Y₁₀ is P₅; R₁ is H; P₁ is Cbz; P₂ isBOM; P₃ is Cbz; and P₅ is Cbz.
 5. A method according to claim 2 whereinX is OR₄; X₁ is R₁P₁; X₂ is isobutyl; X₃ is P₂; Y₇ is P₃; Y₉ is aketone; Y₁₀ is P₅; R₁ is H; P₁ is Boc; P₂ is BOM; P₃ is Cbz; and P₅ isCbz.
 6. A method according to claim 2 wherein X is a halogen; X₂ isisobutyl; Y₇ is P₃; Y₉ is a ketone; Y₁₀ is P₅; R₁ and R₂ areindependently H or substituted or unsubstituted: alkyl, alkenyl, aryl,aralkyl, or acyl; R₃ is H; P₁ is Boc; P₂ is BOM; P₃ is Cbz; and P₅ isCbz.
 7. A method according to claim 1 wherein said third compound hasthe formula:


8. A method according to claim 7 wherein said third compound isconverted to docetaxel, paclitaxel, or a 7,9-acetal linked analog.
 9. Amethod according to claim 7 wherein said third compound is deprotectedby substituting hydrogen for P₁, P₂, P₃ and P₅ to form a fourth compoundhaving the formula:


10. A method according to claim 7 wherein said third compound isdeprotected by substituting hydrogen for P₃, and P₅ to form a fourthcompound having the formula:


11. A method according to claim 10 wherein said fourth compound isselectively acylated at the C-10 position to form a fifth compoundhaving the formula:


12. A method according to claim 11 wherein said fifth compound isconverted to paclitaxel.
 13. A method according to claim 7 wherein saidthird compound is oxidized to form a fourth compound of the formula:


14. A method according to claim 13 wherein said fourth compound isreduced to form a fifth compound of the formula:


15. A method according to claim 14 wherein said fifth compound isacylated at the C-10 position to form a sixth compound of the formula:


16. A method according to claim 15 wherein said sixth compounddeprotected by substituting hydrogen for P₃ thereby to form a seventhcompound of the formula:


17. A method according to claim 16 wherein said seventh compound isconverted to an eighth compound of the formula:

wherein R₁₂ and R₁₃ are independently H; substituted or unsubstituted:alkyl; alkenyl; aryl; aralkyl; or acyl.
 18. A method according to claim17 wherein R₁₂ and R₁₃ are each independently selected from the groupconsisting of:


19. A method according to claim 1 wherein said third compound has theformula


20. A method according to claim 19 wherein said third compound isconverted to paclitaxel.
 21. A method according to claim 1 wherein thefirst compound is a cyclic structure wherein the C-3 Nitrogen and theC-2 Oxygen are linked by a common protecting group that includes R₁ andR₂ and that has the formula:

such that the third compound is a cyclic structure having the formula:

wherein R₃ is either H or P₁.
 22. A method according to claim 21 whereinthe second compound has a structure

Y₇ is R₇; P₃; or Z₇; Y₉ is H; hydroxyl; a ketone; OR₉; P₄; or Z₉; Y₁₀ isR₁₀; P₅; or Z₁₀; Z₇ is P₃ and together with Y₉ forms a cyclic structurewhen Y₉ is P₄; Z₉ is either: P₄ and together with Y7 forms a cyclicstructure when Y₇ is P₃; or P₅ and together with Y₁₀ forms a cyclicstructure when Y₁₀ is P₄; Z₁₀ wherein P₅ forms a cyclic structure withP₄; R₇ is H, substituted or unsubstituted: alkyl, alkenyl, aryl,aralkyl, or acyl; R₉ is a substituted or unsubstituted: alkyl, alkenyl,aryl, aralkyl, or acyl; R₁₀ is H, substituted or unsubstituted: alkyl,alkenyl, aryl, aralkyl, or acyl; P₃ is a hydroxyl protecting group; P₄is a hydroxyl protecting group; and P₅ is a hydroxyl protecting group.23. A method according to claim 22 wherein X is a halogen; X₂ is Ph; Y₇is P₃; Y₉ is a ketone; Y₁₀ is P₅; R₁ is H; P₁ is Boc; P₂ is BOM; P₃ isCbz; and P₅ is Cbz.
 24. A method according to claim 21 wherein X isfluorine; X₁ is R₁P₁; X₂ is Ph; X₃ is P₂; Y₇ is P₃; Y₉ is a ketone; Y₁₀is P₅; R₁ is H; P₁ is Cbz; P₂ is BOM; P₃ is Cbz; and P₅ is Cbz.
 25. Amethod according to claim 22 wherein X is OR₄; X₁ is R₁P₁; X₂ isisobutyl; X₃ is P₂; Y₇ is P₃; Y₉ is a ketone; Y₁₀ is P₅; R₁ is H; P₁ isBoc; P₂ is BOM; P₃ is Cbz; and P₅ is Cbz.
 26. A method according toclaim 22 wherein X is a halogen; X₂ is isobutyl; Y₇ is P₃; Y₉ is aketone; Y₁₀ is P₅; R₁ and R₂ are independently H or substituted orunsubstituted: alkyl, alkenyl, aryl, aralkyl, or acyl; R₃ is H; P₁ isBoc; P₂ is BOM; P₃ is Cbz; and P₅ is Cbz.
 27. A chemical compound havingthe formula:

X is a halogen or OR₄; X₁ is either R₁R₂; R₁P₁; R₂P₁; or P₁P₁ X₂ is asubstituted or unsubstituted: alkyl, alkenyl, aryl, aralkyl, or acyl; X₃is either R₁; R₂; or P₂; R₁ and R₂ are independently H or substituted orunsubstituted: alkyl, alkenyl, aryl, aralkyl, or acyl; R₄ is asubstituted or unsubstituted: alkenyl, aryl, aralkyl, acyl, alkoxycarbonyl, aroyl or aryloxy carbonyl; P₁ is an amine protecting group; P₂is a hydroxyl protecting group.
 28. A chemical compound according toclaim 27 wherein X is selected from the group consisting of chlorine,bromine, fluorine, and iodine.
 29. A chemical compound according toclaim 27 is a cyclic structure wherein the C-3 Nitrogen and the C-2Oxygen are linked by a common protecting group that includes R₁ and R₂and that has the formula:

wherein R₃ is either H or P₁.
 30. A chemical compound according to claim29 wherein X is selected from the group consisting of chlorine, bromine,fluorine, and iodine.
 31. A chemical compound according to claim 29wherein X is chlorine; X₂ is isobutyl; R₁ and R₂ are independently H, orsubstituted or unsubstituted: alkyl, alkenyl, aryl, aralkyl or acyl; R₃is P₁; and P₁ is Boc.
 32. A chemical compound according to claim 31having the structural formula:


33. A chemical compound according to claim 29 wherein X is R₄; X₂ isisobutyl; R₁ and R₂ are independently H, or substituted orunsubstituted: alkyl, alkenyl, aryl, aralkyl or acyl; R₃ is P₁, R₄ istrimethylacetyl; and P₁ is Boc.
 34. A chemical compound according toclaim 33 having the structural formula:


35. A chemical compound according to claim 27 wherein X is OR₁₁; X₁ isR₁P₁; X₂ is isobutyl; X₃ is P₂; R₁ is H; R₁, is H; P₁ is Boc; and P₂ isBOM.
 36. A chemical compound according to claim 35 having the structuralformula:


37. A chemical compound according to claim 27 wherein X is fluorine; X₁is R₁P₁; X₂ is isobutyl; X₃ is P₂; R₁ is H; P₁ is Boc; and P₂ is BOM.38. A chemical compound according to claim 37 having the structuralformula:


39. A chemical compound according to claim 27 wherein X is OR₁₁; X₁ isR₁P₁; X₂ is Ph; X₃ is P₂; R₁ is H; R₁₁ is H; P₁ is Cbz; and P₂ is BOM.40. A chemical compound according to claim 39 having the structuralformula:


41. A chemical compound according to claim 27 wherein X is fluorine; X₁is R₁P₁; X₂ is Ph; X₃ is P₂; R₁ is H; P₁ is Cbz; and P₂ is BOM.
 42. Achemical compound according to claim 41 having the structural formula:


43. A compound according to claim 29 wherein X is R₄; X₂ is aryl,substituted aryl, heteroaryl or substituted heteroaryl; R₁ and R₂ aremethyl; R₃ is P₁, R₄ is trimethylacetyl; and P₁ is Boc.
 44. A compoundof the formula:

X is a halogen or OR₄; R₁ and R₂ are independently H or substituted orunsubstituted: alkyl, alkenyl, aryl, aralkyl, or acyl; R₃ is an amineprotecting group; R₄ is a substituted or unsubstituted: alkenyl, aryl,aralkyl, acyl, alkoxy carbonyl, aroyl or aryloxy carbonyl.
 45. Acompound of the formula